As oil is lighter than water in solutions of water and oil, such as coolants employed with cutting tools, the oil collects on the surface of the body of liquid and devices are known for removing the oil from the liquid.
Oil skimming or other floating material separators utilize rotary discs, webs, ropes and endless belts which pass through the surface of the liquid and as the oil adheres to the moving collector it can be removed therefrom by squeezing or scraping operations. United States patents disclosing oil separating devices of the endless belt or web type are shown in U.S. Pat. Nos. 3,314,545; 3,508,663; 3,640,394; 3,709,369; 4,154,683; 4,274,957; 4,652,372 and 4,582,604. Such patents employ pressure rollers or scrapers to remove the oil from the belt or web and prior art devices have encountered problems in efficiently removing the oil without reintroducing a substantial portion thereof back into the body of liquid being processed which significantly lowers the efficiency of separation.
Oil skimmers using flexible belts and webs can be more concisely constructed than oil removing apparatus using rigid collectors such as rotating discs. However, oil collectors using flexible belts and webs often use doctor and scraper blades for removing the oil from the blade, but such devices require constant maintenance and replacement in view of the high wear occurring.
Oil skimmers of the belt type utilizing the pressure of rollers to remove the oil from the belt do not wear the belt or web to the extent of doctor or scraper blades, but problems have been encountered with roller type oil remover systems in dissipating the oil removed from the belt by the roller pressure. Such problems with respect to oil removal from a belt have been successfully overcome by the oil removing apparatus shown in the assignee's U.S. patent application Ser. No. 07/469,352 filed Jan. 24, 1990, wherein the primary drive roller axis of rotation is substantially vertically oriented. In such apparatus the oil collecting belt is necessarily twisted as it passes about the vertically oriented upper drive roller and passes under the lower horizontally oriented weight roller submerged in the liquid being processed, and the twisted belt configuration of this construction, while highly advantageous with most installations, creates problems where an exceptionally long oil collecting belt must be used.
It is an object of the invention to provide apparatus of the oil removing or skimming type utilizing a flat belt or web wherein the belt is threaded over the upper portion of a primary drive roller having a horizontal axis of rotation and the oil is removed by pressure rollers maintaining the belt in engagement with the primary roller, and yet the removed oil is readily collected below the primary and pressure rollers.
Another object of the invention is to provide oil skimming apparatus of the endless belt type which reduces belt wear and has a high oil removal efficiency, and may be used in installations requiring endless belts of considerable length.
A further object of the invention is to provide oil skimming apparatus of the endless belt type utilizing a substantially horizontally disposed drive roller having pressure rollers located upon opposite sides of the drive roller maintaining the endless oil collecting belt in firm engagement with the drive roller wherein the collected oil is removed from the belt by roller pressure.
An additional object of the invention is to provide belt type oil skimming apparatus employing pressure rollers in conjunction with a primary drive roller wherein the pressure rollers are mounted upon linkage sets biased toward the drive roller for maintaining firm engagement of the pressure rollers with the belt and the belt in engagement with the drive roller, the linkage sets including an actuator for displacing the pressure rollers away from the drive roller to permit easy belt removal and new belt installation.
Another object of the invention is to provide belt type oil skimming apparatus employing a substantially horizontally disposed drive roller in conjunction with a plurality of pressure rollers located upon opposite sides of the drive roller wherein the drive rollers are mounted upon a pair of linkage sets, and each set also includes a belt reversing roller to permit the desired orientation of the belt to the associated pressure roller, and the reversing rollers are mounted upon their associated linkage set in such a manner as to permit ease of removal during endless belt replacement.
Yet another object of the invention is to provide oil skimming apparatus of the endless belt type wherein a pair of pressure rollers are located upon opposite sides of a horizontally disposed primary drive roller, and the axes of rotation of the drive roller and at least one of the pressure rollers are obliquely oriented to aid in the removal of collected oil from the belt under gravitational forces.
In the practice of the invention a frame supports a roller unit assembly, and the frame may be mounted adjacent a reservoir containing the liquid from which oil is to be removed. The frame may be mounted directly to a machine tool having such a reservoir, or the frame may be mounted upon a portable collecting receptacle which may be located adjacent the body of liquid to be treated. Preferably, the frame is vertically adjustably mounted upon its support and the frame includes a housing for an electric motor which rotates a primary drive roller about a substantially horizontal axis.
The endless oil collecting belt is threaded over the upper portion of the drive roller and a pair of pressure rollers are mounted upon the frame adjacent the primary roller on opposite sides thereof and the pressure rollers are mounted upon linkage sets which are spring biased toward the drive roller such that the pressure rollers may engage the belt and maintain the belt in a frictional relationship with the drive roller. The linkage sets also include belt reversing rollers whereby the belts engage almost one-half of the circumference of the pressure rollers assuring effective oil removal. The primary drive roller is of a cantilever configuration having a free end whereby the oil collecting belt may be easily inserted over the drive roller end, or removed therefrom, and as the endless belt engages the underside of the pressure rollers in a freely accessible manner, and as the reversing rollers may be easily temporarily removed from their associated linkage sets during belt replacement, it is possible to change the endless belt without requiring special tools or skills.
The lower end of the endless belt extends into the liquid to be processed, and a weighted roller maintains the configuration of the belt during operation.
A V-shaped collection receptacle is located beneath the roller unit for collecting the oil removed from the belt as it falls under gravitational forces to the collection receptacle. Collected oil flows from the collection receptacle to a collecting reservoir.
In an embodiment of the invention the axis of the pressure roller may be slightly inclined to the horizontal in a non-parallel relationship to the primary drive roller axis to aid in the flow of removed oil from the "upper" portion of the belt as it engages the pressure roller.